The monitoring of biodiversity in response to environmental changes still much depends on human observers, and greatly relies on the activity of volunteers. Large data bases have been developped over time, following more or less standardized protocols. Butterflies* are the group of animals most studied after birds to evaluate the consequences of global changes on biodiversity. Standard Butterfly Monitoring Schemes (BMS) provide large quantities of data on population distribution and tendencies in an increasing number of countries. Data analyses have shown important changes in this component of biodiversity. Little is known as to how these changes are organized along spatial scales however, although the data available constitute a fantastic opportunity to understand the mechanisms and key factors explaining the dynamics of butterfly biodiversity. For instance, we know that species from open habitats have suffered a 70% population lossover the last 20 years in Europe, but few studies have searched to understand how this decline occurred over time and space and how these patterns of variation at different scales also vary between species.

Our project will analyse this type of data from the most local to the most global scales to fill this knowledge gap. It aims at understanding how species ecological traits and environmental factors (habitat and climate) influence the population dynamics at these different scales. To this end, we gathered a consortium of experts to analyse data collected in Europe, Northern America and Israel. Beyond a better understanding of how these species respond to global changes, we will improve the quality of both the mechanisms by which information circulates between countries, and of the analyses that can be conducted jointly, opening a way to sustained scientific interactions . In particular, we will contribute to the development of analytical tools for the various coordinators of of monitoring schemes, as well as for more opportunistic and less standardised types of monitorings.